The need to provide lightweight skidways for small craft to permit them to be launched or drawn-up on a shoreline has previously been recognized. Examples of prior art patents addressing this objective are:
U.S. Pat. No. 3,579,996--Jerry W. Edson PA1 U.S. Pat. No. 3,587,874--Edwin H. Graf PA1 U.S. Pat. No. 4,803,942--Joseph Dren PA1 U.K. 2,116,123--William G. Watson. PA1 U.S. Pat. No. 4,290,728 to Lucien Leduc PA1 U.S. Pat. No. 2,754,017 to H.E. Hart et al PA1 Italy 480,348 to Giacomo Ghiglione.
None of these references provide for an articulated slipway, of extended length, that is readily portable.
Three patents that do propose structures that provide an articulated slipway are:
In the Leduc patent a series of transverse bars are linked together by chains in a ladder-like manner. These chain-linked bars are supported between longitudinal stringers to provide a support base for planks used to create a ramp up into the back of a vehicle. However, the chains do not resist collapsing, and it is not readily apparent how this system could be deployed on a beach as a non-collapsible skidway.
In the Hart patent a series of racks bearing rollers are deployed progressively up the side of a beach. The rollers within each rack are rigidly mounted in a rocking frame. The sides of each frame are considerably longer than the width of the rollers, and these individual frames are not readily disassemblable. This system is complex and has according, a considerable cost penalty.
The patent to Ghiglione shows a series of transverse slider bars, depicted as being made of wood, held together in an articulated ladder-like array by a series of rods that interconnect joints mounted at the end of each bar or "rung". The specific structure of Ghiglione relies upon an upper wooden rung upon which the keel of a boat may be slid. This rung is fastened from below to a metal bar that is up-turned at its outside ends to provide a mount for a pin (4) to which inter-rung connecting rods are attached. Thus the connections between the rods and rungs in Ghiglione are not articulated in the lateral direction, and the Ghiglione skidway can not be swerved sideways in a staggered fashion. Further Ghiglione does not use a tubular skidding cylinder which may be rotated to distribute wear.
The articulated detachable structures described are articulated only to be extent that they are flexible in a single transverse or rotational direction. In Leduc the transverse bars are confined laterally by the longitudinal stringers. In Hart, each rack of rollers may be tipped about only one axis. And in Ghiglione, the connecting rods are attached to pins which serve as shafts and limit flexibility to rotation about the axis of such shafts.
None of these references provide a skidway which has the feature of being fully articulated in the sense of being fully articulated, that is to say of being flexible both laterally, in the plane of the skidway, and perpendicularly to the plane of the skidway.
A further need for small boat owners is to provide a turning pad by which boats may be re-oriented, once pulled up onto the beach.
Boats are normally landed bow first when landing on a beach. There is a need for a system by which a boat can be hauled up the track, centered over a pivoting device and turned around to enable a bow-first launch. This is very advantageous for a number of reasons:
Small outboard powered planing hulls have a weight concentration in the stern often combined with a sharp, squared off transom. They will potentially "hang up" on a skidway when skidded along stern first. A turning pad enables boats to be turned 180 degrees and skidded bow first.
A bow-first launch is advantageous when launching into wave conditions.
Furthermore the turning pad enables boats to be handled by a single person or at least fewer people by enabling them to be skidded bow first.
With this background in mind, the invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention will then be further described, and defined, in each of the individual claims which conclude this Specification.